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Jun 26

Mysterious, Gaping Holes in Antarctic Ice Explained

Enormous holes in the Antarctic winter ice pack have popped up sporadically since the 1970s, but the reason for their formation has been largely mysterious.

Scientists, with the help of floating robots and tech-equipped seals, may now have the answer: The so-called polynyas (Russian for “open water”) seem to be the result of storms and salt, new research finds.

Enormous holes in the Antarctic winter ice pack have popped up sporadically since the 1970s, but the reason for their formation has been largely mysterious.

Scientists, with the help of floating robots and tech-equipped seals, may now have the answer: The so-called polynyas (Russian for “open water”) seem to be the result of storms and salt, new research finds.

Polynyas have gotten a lot of attention lately because two very large ones opened in the Weddell Sea in 2016 and 2017; in the latter event, the open waters stretched over 115,097 square miles (298,100 square kilometers), according to an article published in April in the journal Geophysical Research Letters.

Now, the most comprehensive look ever at the ocean conditions during polynya formation reveals that these stretches of open water grow due to short-timescale climate variations and particularly nasty weather. The polynyas also release a lot of deep-ocean heat into the atmosphere, with consequences that scientists are still working out.

“It may modify weather patterns around Antarctica,” study leader Ethan Campbell, a doctoral student in oceanography at the University of Washington, told Live Science. “Possibly farther.”

Researchers already suspected that storms had some role in the creation of polynyas in recent years. A paper published in April by atmospheric scientists in the Journal of Geophysical Research: Atmospheres pointed to a particularly violent storm with wind speeds up to 72 miles per hour (117 kilometers per hour) in 2017.

But even though the winter storms of 2016 and 2017 were extreme, stormy seas are the norm in the Antarctic winter, Campbell said.

“If it were only storms, we’d see polynyas all the time, but we don’t,” he said. Instead, large polynyas are relatively rare. There were three huge ones in 1974, 1975 and 1976, but nothing significant again until 2016.

Campbell and his team drew data from two robotic, human-size floats that were deployed in the Weddell Sea by the National Science Foundation-funded Southern Ocean Carbon and Climate Observations and Modeling project (SOCCOM). The floats drift in the currents about a mile below the ocean’s surface, Campbell said, collecting data about water temperature, salinity and carbon content.

For comparison purposes, the researchers also used year-round observations from Antarctic research vessels and even scientific seals — wild pinnipeds fitted with small instruments to collect ocean data as the animals conduct their usual travels.

Read the full story at Live Science